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Main Authors: Hung, Tzu-Chao, Godinez-Loyola, Yokari, Steinbrecher, Manuel, Kiraly, Brian, Khajetoorians, Alexander A., Doltsinis, Nikos L., Strassert, Cristian A., Wegner, Daniel
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2307.09984
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author Hung, Tzu-Chao
Godinez-Loyola, Yokari
Steinbrecher, Manuel
Kiraly, Brian
Khajetoorians, Alexander A.
Doltsinis, Nikos L.
Strassert, Cristian A.
Wegner, Daniel
author_facet Hung, Tzu-Chao
Godinez-Loyola, Yokari
Steinbrecher, Manuel
Kiraly, Brian
Khajetoorians, Alexander A.
Doltsinis, Nikos L.
Strassert, Cristian A.
Wegner, Daniel
contents Luminescence of open-shell 3d metal complexes is often quenched due to ultrafast intersystem crossing (ISC) and cooling into a dark metal-centered excited state. We demonstrate successful activation of fluorescence from individual nickel phthalocyanine (NiPc) molecules in the junction of a scanning tunneling microscope (STM) by resonant energy transfer from other metal phthalocyanines at low temperature. By combining STM, scanning tunneling spectroscopy, STM- induced luminescence, and photoluminescence experiments as well as time-dependent density functional theory, we provide evidence that there is an activation barrier for the ISC, which in most experimental conditions is overcome. We show that this is also the case in an electroluminescent tunnel junction where individual NiPc molecules adsorbed on an ultrathin NaCl decoupling film on a Ag(111) substrate are probed. However, when placing an MPc (M = Zn, Pd, Pt) molecule close to NiPc by means of STM atomic manipulation, resonant energy transfer can excite NiPc without overcoming the ISC activation barrier, leading to Q-band fluorescence. This work demonstrates that the thermally activated population of dark metal-centered states can be avoided by a designed local environment at low temperatures paired with a directed molecular excitation into vibrationally cold electronic states. Thus, we can envisage the use of luminophores based on more abundant transition metal complexes that do not rely on Pt or Ir.
format Preprint
id arxiv_https___arxiv_org_abs_2307_09984
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Activating the fluorescence of a Ni(II) complex by energy transfer
Hung, Tzu-Chao
Godinez-Loyola, Yokari
Steinbrecher, Manuel
Kiraly, Brian
Khajetoorians, Alexander A.
Doltsinis, Nikos L.
Strassert, Cristian A.
Wegner, Daniel
Mesoscale and Nanoscale Physics
Materials Science
Chemical Physics
Luminescence of open-shell 3d metal complexes is often quenched due to ultrafast intersystem crossing (ISC) and cooling into a dark metal-centered excited state. We demonstrate successful activation of fluorescence from individual nickel phthalocyanine (NiPc) molecules in the junction of a scanning tunneling microscope (STM) by resonant energy transfer from other metal phthalocyanines at low temperature. By combining STM, scanning tunneling spectroscopy, STM- induced luminescence, and photoluminescence experiments as well as time-dependent density functional theory, we provide evidence that there is an activation barrier for the ISC, which in most experimental conditions is overcome. We show that this is also the case in an electroluminescent tunnel junction where individual NiPc molecules adsorbed on an ultrathin NaCl decoupling film on a Ag(111) substrate are probed. However, when placing an MPc (M = Zn, Pd, Pt) molecule close to NiPc by means of STM atomic manipulation, resonant energy transfer can excite NiPc without overcoming the ISC activation barrier, leading to Q-band fluorescence. This work demonstrates that the thermally activated population of dark metal-centered states can be avoided by a designed local environment at low temperatures paired with a directed molecular excitation into vibrationally cold electronic states. Thus, we can envisage the use of luminophores based on more abundant transition metal complexes that do not rely on Pt or Ir.
title Activating the fluorescence of a Ni(II) complex by energy transfer
topic Mesoscale and Nanoscale Physics
Materials Science
Chemical Physics
url https://arxiv.org/abs/2307.09984